User Guide

6015/6015i/6016i/6019i (RH-55), 6012 (RM-20)

System Module Nokia Customer Care

TTY/TTD and Universal Headset Jack

TTYTTD devices use a standard 2.5mm 3-pin plug (tip = transmit, ring = receive, sleeve =

ground) and the universal headset also uses same type of plug (tip = microphone, ring =

earpiece, sleeve = ground). Because only three pins are available for both transmitting

and receiving at the same time, both paths have to use single-end design (share the

ground). The detection scheme for this interface uses a built-in switch (which is normally

closed) in the universal headset jack. When there is no device being plugged in, the

switch is closed, which forces the level on the detection line (GENIO[21]) to 1.8V. When a

device is plugged in, the voltage is set to 0V. The detection line can then identify

whether a device is plugged in.

Charger IF

The charger connection is implemented through the bottom connector. DCT-4 bottom

connector supports charging with both plug chargers and desktop stand chargers. There

are three signals for charging. A charger ground pin is used for both the desktop and for

the plug chargers. Charger voltage and the PWM control line, which is needed for 3-wire

chargers, is connected directly to the ground in the PWB so the engine does not provide

any PWM control to chargers. Charge controlling is done inside UEM by switching the

UEM internal charger switch on/off.

The fuse (F100) protects from high currents (e.g., when broken or pirate chargers are

used). L100 protects the engine from RF noises that may occur in the charging cable.

D100 protects the UEM ASIC from reverse polarity charging and from high charging

voltage. C106 also is used for ESD and EMC protection.

Test Interfaces

Production Test Pattern

The interface for production testing is a 5-pin pad layout in the BB area (see Figure 8).

The production tester connects to these pads using spring connectors. The interface

includes the MBUS, USRX, FBUSTX, VPP, and GND signals, and the pad size is 1.7mm. The

same pads also are used for AMS test equipment (e.g., module jig, service cable).

Figure 8: 5-pin Pad Layout in BB area

FBUS_RX

GND

VPP

MBUS

FBUS_T